CZELITE,
I am talking about the recoil spring. I have no beef with Wolff springs, as you said.
It's a fact that autopistols that operate generally like a CZ, Glock, 1911, etc, depend on both slide velocity relative to the frame, and "enough" slide motion relative to the frame. If it's going too slow, it may fail to eject or clear the port. If it doesn't reach its rearward limit, it may fail to eject, fail to strip the next round, fail to chamber it properly, or fail to lock the slide back on the last round.
To see these failures occur, just keep increasing the recoil spring strength. Alternatively, shoot extra-low power rounds in your factory-sprung CZ to see the same effects. You should start to see such failures with a 115gr around 850-900fps in a CZ. 115gr@900 will not operate a Glock. I have not done experiments to see how much one must increase spring strength to induce the same failures using factory ammo.
For a pistol in a defensive role, I want the most margin between each firing event's conditions and the various failure conditions. In the case of the recoil spring, there will be an upper and lower limit to this "reliable" range. Spring it too low, and the gun will probably unlock too soon, putting extra stress on the case itself (not to mention frame battering). Spring it too high, and the gun will hit those failure modes listed above. In a defensive situation, I want to avoid both problems, taking into account factors that can change the conditions that effect operation of the pistol.
Examples of these might be: limp-wristing for whatever reason, maybe I'm in a 1-handed retention hold; maybe the cartridge fired is on the extreme low spread of the deviation; maybe the slide is extra gunked up; maybe my thumb rubs against the slide, etc, etc. Some of these may never be a problem in normal training and practice, but may be if me and my equipment are pushed.
If I follow your advice and pick the next spring below the one that produces failures, then there is less margin between the average conditions and the failure conditions, than if I stayed with the weaker stock-weight spring.
BTW, I do agree that increasing the spring weight may alleviate my feeding problems, since the cartridge will have more force pushing it up the ramp.
regards
Zak